oblichey-cli panics with "Failed to get log directory: EnvVar(NotPresent)" on NixOS (flakes)

[Meo98]

Title

oblichey-cli panics with "Failed to get log directory: EnvVar(NotPresent)" on NixOS (flakes)

---

Summary

On NixOS using flakes, oblichey-cli panics immediately with:

Failed to get log directory: EnvVar(NotPresent)

This happens even when I set XDG_STATE_HOME and other XDG/XDG-like variables via NixOS configuration.

---

Environment

$ nixos-version
25.11.20251112.c5ae371 (Xantusia)

$ nix --version
nix (Nix) 2.31.2

$ uname -a
Linux nixos 6.17.7 #1-NixOS SMP PREEMPT_DYNAMIC Sun Nov  2 13:18:05 UTC 2025 x86_64 GNU/Linux

---

Nix flake configuration

flake.nix:

{
  description = "NixOS Configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    zen-browser.url = "github:0xc000022070/zen-browser-flake";
    oblichey.url = "github:SimonBrandner/oblichey/main";
  };

  outputs = inputs@{ self, nixpkgs, oblichey, ... }: {
    nixosConfigurations.nixos = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      specialArgs = { inherit inputs; };
      modules = [ ./configuration.nix ];
    };
  };
}

configuration.nix (relevant part):

{ config, pkgs, inputs, ... }:

{
  imports = [
    ./hardware-configuration.nix
    inputs.oblichey.nixosModules.default
  ];

  environment.sessionVariables = rec {
    XDG_CACHE_HOME  = "$HOME/.cache";
    XDG_CONFIG_HOME = "$HOME/.config";
    XDG_DATA_HOME   = "$HOME/.local/share";
    XDG_STATE_HOME  = "$HOME/.local/state";
    NIXOS_OZONE_WL  = "1";
  };

  security.pam.services.sudo.setEnvironment = true;
  security.pam.services.login.setEnvironment = true;

  programs.oblichey = {
    enable = true;
    pamServices = [ "sudo" "login" ];
    settings = {
      camera = {
        path = "/dev/video2";
      };
    };
  };
}

---

Steps to reproduce

1. Rebuild NixOS with the configuration above.
2. As my normal user, run:

mkdir -p ~/.local/state/oblichey
RUST_BACKTRACE=1 XDG_STATE_HOME="$HOME/.local/state" oblichey-cli help

The panic also happens for:

RUST_BACKTRACE=1 XDG_STATE_HOME="$HOME/.local/state" oblichey-cli scan --label meo

and when Oblichey is called via PAM (e.g. sudo).

---

Actual behavior

The CLI panics instead of running:

thread 'main' panicked at crates/oblichey-cli/src/main.rs:58:45:
Failed to get log directory: EnvVar(NotPresent)
stack backtrace:
   0: rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::result::unwrap_failed
   3: oblichey_cli::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

---

Expected behavior

If no log directory can be determined, oblichey-cli should either:

• fall back to a sensible default (e.g. $XDG_STATE_HOME/oblichey), or
• print a clear error message and exit gracefully (without panicking).

Let me know if you need more info or if I can test a patch.

[SimonBrandner]

Hi, I am sorry for a late response.

I do not immediately see what exactly is going wrong... Can you run env | grep XDG_CACHE_HOME to check if it is set properly? You can also try running Oblichey with XDG_CACHE_HOME=/path/to/cache oblichey-cli help.

I am quite busy with school atm, so I am not sure when I can get to properly debugging this. However, I am happy to review and accept a PR (if by chance you had the time and knowledge to debug this)!

(I also wanted to mention that oblichey can currently give false positives)